Re: Are these too harsh ?

Connor McDonald wrote:

> I'm currently assisting in the interviewing for a DBA - the company is not
> looking for an "Einstein", but also not a junior, just someone who can do
> the job adequately. I was asked to come up with a list of DBA questions, so
> I produced a set that was created for exactly the same purpose at a previous
> site. But so far, no one has explained more than about 60% to an acceptable
> degree.
>
> So I'm looking for impartial opinions - are the following questions too hard
> ?
>
> Ta
> Connor
>
> - What are the various shutdown modes for the database?
> - Describe the basic mechanics of how hot backup works?
> - Besides the overhead of copying the files to disk/tape, what other
> performance issues are relevant during a hot backup, namely, why do many
> sites try to keep the time spent in backup mode to a minimum?
> - If I need to export a single 40G table, but only have 5 separate file
> system, each of only 10G, for the export file - what measures could you
> take?
> - What is the standby database feature and how does it work?
> - List the steps that Oracle goes through at database startup
> - What is the difference between a latch and a lock? Give an example of use
> of each
> - What is "spinning" as it pertains to a latch?
> - What are the positives and negatives of a large database block size on
> indexes?
> - What is the Oracle log buffer? Describe how Oracle uses latches as
> information is written into the log buffer
> - What is a function-based index and where could it be used?
> - What is the 8i feature "Native Dynamic SQL"?
> - What is a locally managed tablespace and list some benefits
> - How do I allow end-user queries against a standby database without
> damaging its ability to act as a standby?
> - What are the significant features of "analytic functions" available from
> 8.1.6 onwards ?
> - What does the "explain plan" command do
> - On a Unix machine, you see an oracle process using all of the CPU.
> Assuming it is due to a poorly written SQL, describe how to determine the
> SQL that is causing the problem, starting with the Unix process ID.
> - How would you determine the amount of I/O occurring on each datafile in
> the database ? If a great deal of this is occurring on the TEMP tablespace
> what is the likely cause ?
> - Describe the three buffer pools (available in 8.0 and 8i) and their uses ?
> - List the pros and cons of using bind variables
> - You issue 'select count(*) from my_table;' and it takes a tremendously
> long time, but then return no rows. What could be causing this ?
> - Describe the common RAID levels used for Oracle databases and how they
> typically pertain to performance
> - Describe how you would determine whether an index requires rebuilding ?
> - What are the advantages of creating code using packages over standalone
> PL/SQL procedures
> - Describe how and why a PL/SQL module could be defined as an autonomous
> transaction
> - Your database contains a view, which joins two tables. It is possible to
> insert, update, and delete rows from this view. - Describe two ways of
> implementing this.
> - What is an inline view?
>
> --
> ==============================
> Connor McDonald
>
> http://www.oracledba.co.uk
>
> "Some days you're the pigeon, some days you're the statue..."

I think most of your questions are irrelevant depending on what you expect the person to do. They look to me like a blend of development, DBA, sys admin, and irrelevant designed to make sure no one gets the job.

The first question I'd ask is what are the tasks you want the person to do. Then I'd ask what each of these questions has to do with that task list. Most production DBAs wouldn't meet an autonomous transaction in their normal daily activities and most Development DBAs wouldn't know a latch if it wasn't attached to a gate in their front yard. (Not all guys so don't hit me too hard ... you know what I'm getting at.)

Throw these questions away and write questions that will specifically test the candidate's ability to perform the tasks that will be assigned.

Daniel A. Morgan Received on Mon Jun 25 2001 - 15:16:43 CDT